This invention relates to polydiacetylenes and more particularly to the chemical modification of crystalline polydiacetylenes.
Polydiacetylenes are a class of fully ordered crystalline polymers which are of value as nonlinear optical elements, photoconductors, time-temperature indicators, and photoresists. Good thermal and mechanical properties have also been reported for this class of materials. While certain polydiacetylenes with relatively long side chains may be dissolved in selected solvents, many of the widely studied polydiacetylenes are insoluble. With respect to chemical reactivity of polydiacetylenes with external reagents, relatively little detailed information is available.
Crystalline polydiacetylenes can be prepared from diacetylene compounds by solid state polymerization techniques. The crystallinity of polydiacetylenes is a consequence of their synthesis via lattice controlled solid state polymerization when subjected to thermal or assorted radiative excitations. The polydiacetylenes occupy a key position among organic materials which exhibit phenomena manifesting delocalized interactions due to wide electronic bands. Moreover, polydiacetylenes are often available in processed form.
Beyond structural studies of monomers and polymers, studies of the mechanistic aspects of the polymerization, and the usual spectroscopic studies, only two seminal reports have appeared which show promise of a significant broadening of the scope of polydiacetylene research. They are the report of very high values of the third order nonlinear susceptibility (.chi..sup.(3)) in single crystal poly-PTS, (bis -p-toluene sulfonate of 2.4-hexadiyne-1,6-diol) with major implications for optical signal processing, and reports of electronic carrier mobilities (.mu.) comparable to Si and GaAs in single crystals of poly-PTS and -DCH (1,6-di-N-carbazolyl-2,4-hexadiyne), suggesting potential as novel electronic materials. While the carrier mobilities are indicated to be high, polydiacetylenes are insulators because, following .sigma.=ne.mu., the number of carriers, n, is extremely low.
Prior to the present invention, controlled chemical modification of crystalline polydiacetylenes involving the formation of covalent bonds in crystalline polydiacetylenes had not been reported.